Police say 28-year-old Melissa Santoro netted less than $300 in the heists.

Police say a clerk at a Sunoco gas station robbed last month and again Tuesday night recognized Santoro when she came in to buy cigarettes. Police say she denied robbing the station. She also denied robbing a Pittsburgh Rite Aid last month and Jet's Pizza in neighboring Dormont on Tuesday night.

But police say after taking a lie detector test, Santoro confessed to all four robberies.

She told them a gun she carried was plastic, and she needed money for her pets and to help her mother.